Have a real, at least for me, headscratcher. Site recently installed SV9100 with PRI. Migrated from hosted. Everything seemed to work well until they mentioned that callers calling in will report that they hear ringing even after the call is answered. The party on the PBX says they can hear the caller but cannot be heard. This happens to analog or digital users. I tried replacing the PRI card and it seemed to solve the trouble but it has been reported to come back. The service provider says not them. I have run D-Channel traces and both tech support and I can see nothing wrong there. I am trying to avoid visiting the site with a PRI tester as it is very remote. If I go, I will be prepared to replace the cabinet and CPU if I cannot prove to myself it is the SP.
I am writing in the hope someone out there may have run across this or can offer some meaningful troubleshooting. I have remote access to the system.
Of course, I have made about 100 test calls to this thing and can't duplicate it.
Thank You ~ Mike
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I am positive like 99.9% you have a carrier issue. I would go down each channel selecting it #9+001 etc until you find the bad T1 channel. This can also be a glare issue if they are busy and you don't have the lines ascending descending properly (I doubt this) but high volume it can happen.
@Coral Tech. Thank you. I did double check to be sure the trunk group order was set with channel 23 being the first selected channel and channel being number 23. I will keep the #9 trick in my hat. Looking like a site visit is needed. ~ Mike
I went to site Thursday night with an ISDN-PRI tester. I jacked into the monitor ports on the CSU and configured the tester so I could selectively listen to Eq audio and network audio.
Then the fun began with calling in, calling in, calling in, calling in. Could not duplicate trouble. I went back Friday morning and finally was able to get a similar trouble. I called in and there was no audio in either direction. I placed the call on hold so the system would broadcast music on hold and thankfully heard it on the test set so I know the system is doing its thing.
We left the call nailed up while the customer called Level 3 and tried to get them to help. We got the same old run around about the D-Channel setup being good which was never the issue. When we explained there was no audio on a B-Channel, you could hear the deer in the headlights look. The tech was going to open a ticket with T-Mobile (where the call originated from) but I think that is a stop gap.
We tore down the call and, for grins, I tried to replicate it. I did. We then tried 150 test calls from an AT&T wireless with no trouble. I was also not able to recreate the trouble for the rest of my visit from my phone.
I feel much more confident that this is not an NEC issue and I think I won the customer over on my side because I at least visited the site and performed some meaningful testing and could demonstrate logically what was happening.
Sad that carriers no longer test their own stuff anymore. I hope you are billing for this. It's so rare for a PRI to not work anymore on an NEC PBX unless something physical happened to it to damage the card. Then most of the time it just doesn't work at all.